Does it sound like thrush? DS does have new teeth but I don't think he's biting. Feels more like a tight, pulling sensation and is currently only on one side. I had severe ductal thrush several times when BFing DD and this is nothing like the pain of that.
I'm taking antibiotics for mastitis, which was in the other breast to this pain. He's not feeding much off the mastitis side (always the least favoured anyway). He is also on antibiotics for a chest and throat infection and seems to have thrush in his nappy area (seen by GP - treating with canestan).
I do not have access to any good local RL help, unfortunately.